1. Field of the Invention
The present invention relates to a display device, and more particularly, to a display device including a plurality of pixel circuits provided on a substrate.
2. Description of the Related Art
In a display device including a plurality of pixel circuits formed on a planar substrate, a short circuit may occur by static electricity during manufacturing, and product failure may occur in some cases (hereinafter, this phenomenon is referred to as electrostatic discharge damage). For example, as a measure for preventing the electrostatic discharge damage in a liquid crystal display device, a bidirectional diode is provided between wiring lines which have possibility of being short-circuited.
Further, as another measure for preventing the electrostatic discharge damage, a resistor element may be used to connect a plurality of wiring lines which have possibility of being short-circuited, as disclosed in Japanese Patent No. 3429775.
The bidirectional diode and the resistor element provided between the wiring lines, which are used as conventional countermeasures against the electrostatic discharge damage, are formed of two conductive layers provided on the substrate and a semiconductor layer provided between the two conductive layers. In the manufacturing steps, the electrostatic discharge damage cannot be prevented until those elements are formed. Therefore, it is impossible to prevent the electrostatic discharge damage which occurs in a step of, for example, forming the upper conductive layer by sputtering. Further, the circuit design is greatly restricted.